J80 is a Z80 emulator with a standard BIOS for a complete Microcomputer with working CP/M 2.2, CP/M 3.0, and one simple ZX Spectrum 48/128K emulator. The spectrum 128K version emulation is incomplete but working. The goal of this emulator is that the 'hardware' is built on-the-fly, reading the configuration from one file. This makes it very easy to add new peripherals or features.
Yet Another Machine Simulator (YAMS) is a simple yet realistic machine simulator, which is mainly aimed for teaching purposes on operating systems courses. It simulates one or more MIPS32 CPUs and I/O devices such as disks, terminals, and network cards. Additional devices can be implemented as separate programs that use its I/O plugin interface. The device properties are very configurable. High performance was not a priority factor in its implementation since the main purpose is educational, so YAMS is not an answer for people looking for a fast MIPS emulator/simulator.
AtariSIO is a Linux kernel driver module plus a small set of tools that implement the Atari 8-bit (400/600/800/XL/XE) computer series SIO protocol. The kernel driver handles the low-level parts and provides a simple interface for user space applications. This package contains two tools: atariserver, an Atari disk drive emulator (similar to SIO2PC or APE for MSDOS), and atarixfer, a tool to transfer disk images to/from a connected Atari disk drive.
PalmOrb is software that allows you to use your PalmOS device as an LCD status display for your computer. You can display system stats (such as CPU load graphs, CPU temperatures, free disk space), news alerts, stock indexes, WinAmp graphs, etc. It works by pretending to be (or emulating) a real LCD (a Matrix Orbital LK204-25). You can use existing software that expects a Matrix Orbital display.
Romeo is a Java-based MAME frontend. It supports XMame and the Windows command line, and it has a lot of features. This application is skinnable. It can automatically download ROMs, screenshots, flyers, and other related types of media. A different config file can be used for each game.